Bacterial meningitis

1
Bacterial meningitis
2
Introduction

• Bacterial meningitis is an inflammation of the
  leptomenings, usually causing by bacterial
  infection.
• Bacterial meningitis may present acutely
  (symptoms evolving rapidly over 1-24 hours),
  subacutely (symptoms evolving over 1-7days), or
  chronically (symptoms evolving over more than 1
  week).

3
Introduction

• Annual incidence in the developed countries is
  approximately 5-10 per 100000.
• 30000 infants and children develop bacterial
  meningitis in United States each year.
• Approximately 90 per cent of cases occur in
  children during the first 5 years of life.

4
Introduction

• Cases under age 2 years account for almost 75 of
  all cases and incidence is the highest in early
  childhood at age 6-12 months than in any other
  period of life.
• There are significant difference in the incidence
  of bacterial meningitis by season.

5
Etiology

• Causative organisms vary with patient age, with
  three bacteria accounting for over three-quarters
  of all cases
• Neisseria meningitidis (meningococcus)
• Haemophilus influenzae (if very young and
  unvaccinated)
• Streptococcus pneumoniae ( pneumococcus)

6
Etiology

• Other organisms
• Neonates and infants at age 2-3 months
• Escherichia coli
• B-haemolytic streptococci
• Staphylococcus aureus
• Staphylococcus epidermidis
• Listeria monocytogenes

7
Etiology

• Elderly and immunocompromised
• Listeria monocytogenes
• Gram negative bacteria
• Hospital-acquired infections
• Klebsiella
• Escherichia coli
• Pseudomonas
• Staphylococcus aureus

8
Etiology

• The most common organisms
• Neonates and infants under the age of 2months
• Escherichia coli
• Pseudomonas
• Group B Streptococcus
• Staphylococcus aureus

9
Etiology

• Children over 2 months
• Haemophilus influenzae type b
• Neisseria meningitidis
• Streptococcus pneumoniae
• Children over 12 years
• Neisseria meningitidis
• Streptococcus pneumoniae

10
Etiology

• Major routes of leptomening infection
• Bacteria are mainly from blood.
• Uncommonly, meningitis occurs by direct extension
  from nearly focus (mastoiditis, sinusitis) or by
  direct invasion (dermoid sinus tract, head
  trauma, meningo-myelocele).

11
Pathogenesis

• Susceptibility of bacterial infection on CNS in
  the children
• Immaturity of immune systems
• Nonspecific immune
• Insufficient barrier (Blood-brain barrier)
• Insufficient complement activity
• Insufficient chemotaxis of neutrophils
• Insufficient function of monocyte-macrophage
  system
• Blood levels of diminished interferon (INF) -?and
  interleukin -8 ( IL-8 )

12
Pathogenesis

• Susceptibility of bacterial infection on CNS in
  the children
• Specific immune
• Immaturity of both the cellular and humoral
  immune systems
• Insufficient antibody-mediated protection
• Diminished immunologic response
• Bacterial virulence

13
Pathogenesis

• A offending bacterium from blood invades the
  leptomeninges.
• Bacterial toxics and Inflammatory mediators are
  released.
• Bacterial toxics
• Lipopolysaccharide, LPS
• Teichoic acid
• Peptidoglycan
• Inflammatory mediators
• Tumor necrosis factor, TNF
• Interleukin-1, IL-1
• Prostaglandin E2, PGE2

14
Pathogenesis

• Bacterial toxics and inflammatory mediators cause
  suppurative inflammation.
• Inflammatory infiltration
• Vascular permeability alter
• Tissue edema
• Blood-brain barrier detroy
• Thrombosis

15
Pathology

• Diffuse bacterial infections involve the
  leptomeninges, arachnoid membrane and superficial
  cortical structures, and brain parenchyma is also
  inflamed.
• Meningeal exudate of varying thickness is found.
• There is purulent material around veins and
  venous sinuses, over the convexity of the brain,
  in the depths of the sulci, within the basal
  cisterns, and around the cerebellum, and spinal
  cord may be encased in pus.
• Ventriculitis (purulent material within the
  ventricles) has been observed repeatedly in
  children who have died of their disease.

16
Pathology

• Invasion of the ventricular wall with
  perivascular collections of purulent material,
  loss of ependymal lining, and subependymal
  gliosis may be noted.
• Subdural empyema may occur.
• Hydrocephalus is an common complication of
  meningitis.
• Obstructive hydrocephalus
• Communicating hydrocephalus

17
Pathology

• Blood vessel walls may infiltrated by
  inflammatory cells.
• Endothelial cell injury
• Vessel stenosis
• Secondary ischemia and infarction
• Ventricle dilatation which ensues may be
  associated with necrosis of cerebral tissue due
  to the inflammatory process itself or to
  occlusion of cerebral veins or arteries.

18
Pathology

• Inflammatory process may result in cerebral edema
  and damage of the cerebral cortex.
• Conscious disturbance
• Convulsion
• Motor disturbance
• Sensory disturbance
• Meningeal irritation sign is found because the
  spinal nerve root is irritated.
• Cranial nerve may be damaged

19
Clinical manifestation

• Bacterial meningitis may present acutely
  (symptoms evolving rapidly over 1-24 hours) in
  most cases.
• Symptoms and signs of upper respiratory or
  gastrointestinal infection are found before
  several days when the clnical manifestations of
  bacterial meningitis happen.
• Some patients may access suddenly with shock and
  DIC.

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Clinical manifestation

• Toxic symptom all over the body
• Hyperpyrexia
• Headache
• Photophobia
• Painful eye movement
• Fatigued and weak
• Malaise, myalgia, anorexia,
• Vomiting, diarrhea and abdominal pain
• Cutaneous rash
• Petechiae, purpura

21
Clinical manifestation

• Clinical manifestation of CNS
• Increased intracranial pressure
• Headache
• Projectile vomiting
• Hypertension
• Bradycardia
• Bulging fontanel
• Cranial sutures diastasis
• Coma
• Decerebrate rigidity
• Cerebral hernia

22
Clinical manifestation

• Clinical manifestation of CNS
• Seizures
• Seizures occur in about 20-30 of children with
  bacterial meningitis.
• Seizures is often found in haemophilus influenzae
  and pneumococal infection.
• Seizures is correlative with the inflammation of
  brain parenchyma, cerbral infarction and
  electrolyte disturbances.

23
Clinical manifestation

• Clinical manifestation of CNS
• Conscious disturbance
• Drowsiness
• Clouding of consciousness
• Coma
• Psychiatric symptom
• Irritation
• Dysphoria
• dullness

24
Clinical manifestation

• Clinical manifestation of CNS
• Meningeal irritation sign
• Neck stiffness
• Positive Kernigs sign
• Positive Brudzinskis sign

25
Clinical manifestation

• Clinical manifestation of CNS
• Transient or permanent paralysis of cranial
  nerves and limbs may be noted.
• Deafness or disturbances in vestibular function
  are relatively common.
• Involvement of the optic nerve, with blindness,
  is rare.
• Paralysis of the 6th cranial nerve, usually
  transient, is noted frequently early in the
  course.

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Clinical manifestation

• Symptom and signs of the infant under the age of
  3 months
• In some children, particularly young infants
  under the age of 3 months, symptom and signs of
  meningeal inflammation may be minimal.
• Fever is generally present, but its absence or
  hypothermia in a infant with meningeal
  inflammation is common.
• Only irritability, restlessness, dullness,
  vomiting, poor feeding, cyanosis, dyspnea,
  jaundice, seizures, shock and coma may be noted.
• Bulging fontanel may be found, but there is not
  meningeal irritation sign.

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Complication

• Subdural effusion
• Subdural effusions occur in about 10-30 of
  children with bacterial meningitis.
• Subdural effusions appear to be more frequent in
  the children under the age of 1 year and in
  haemophilus influenzae and pneumococal infection.
• Clinical manifestations are enlargement in head
  circumference, bulging fontanel, cranial sutures
  diastasis and abnormal transillumination of the
  skull.
• Subdural effusions may be diagnosed by the
  examination of CT or MRI and subdural pricking.

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Complication

• Ependymitis
• Neonate or infant with meningitis
• Gram-negative bacterial infection
• Clinical manifestation
• Persistent hyperpyrexia,
• Frequent convulsion
• Acute respiratory failure
• Bulging fontanel
• Ventriculomegaly (CT)
• Cerebrospinal fluid by ventricular puncture
• WBCgt50109/L
• Glucoselt1.6mmol/L
• Proteingto.4g/L

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Complication

• Cerebullar hyponatremia
• Syndrem of inappropriate secretion of
  antidiuretic hormone (SIADH)
• Hyponatremia
• Degrade of blood osmotic pressure
• Aggravated cerebral edema
• Frequent convulsion
• Aggravated conscious disturbance

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Complication

• Hydrocephalus
• Increased intracranial pressure
• Bulging fontanel
• Augmentation of head circumference
• Brain function disorder
• Other complication
• Deafness or blindness
• Epilepsy
• Paralysis
• Mental retardation
• Behavior disorder

31
Laboratory Findings

• Peripheral hemogram
• Total WBC count
• 20109/L 40109/L WBC
• Decreased WBC count at severe infection
• Leukocyte differential count
• 8090 Neutrophils

32
Laboratory Findings

• Rout examination of cerebrospinal fluid (CSF)
• Increased pressure of cerebrospinal fluid
• Cloudiness
• Evident Increased total WBC count (gt1000109/L)
• Evident Increased neutrophils in leukocyte
  differential count
• Evident Decreased glucose (lt1.1mmol/l)
• Evident Increased protein level
• Decreased or normal chloridate
• CSF film preparation or cultivation positive
  result

33
Laboratory Findings

• Especial examination of CSF
• Specific bacterial antigen test
• Countercurrent immuno-electrophoresis
• Latex agglutination
• Immunofluorescent test
• Neisseria meningitidis (meningococcus)
• Haemophilus influenzae
• Streptococcus pneumoniae ( pneumococcus)
• Group B streptococcus

34
Laboratory Findings

• Especial examination of CSF
• Other test of CSF
• LDH
• Lactic acid
• CRP
• TNF and Ig
• Neuron specific enolase (NSE)

35
Laboratory Findings

• Other bacterial test
• Blood cultivation
• Film preparation of skin petechiae and purpura
• Secretion culture of local lesion
• Imageology examination

36
Diagnosis

• Diagnostic methods
• A careful evaluation of history
• A careful evaluation of infants signs and
  symptoms
• A careful evaluation of information on
  longitudinal changes in vital signs and
  laboratory indicators
• Rout examination of cerebrospinal fluid (CSF)

37
Differential diagnosis

• Clinical manifestation of bacterial meningitis is
  similar to clinical manifestation of viral,
  tuberculous , fungal and aseptic meningitis.
• Differentiation of these disorders depends upon
  careful examination of cerebrospinal fluid
  obtained by lumbar puncture and additional
  immunologic, roentgenographic, and isotope
  studies.

38
Characteristics of CSF on common disease in CNS
39
Treatment Antibiotic Therapy

• Therapeutic principle
• Good permeability for Blood-brain barrier
• Drug combination
• Intravenous drip
• Full dosage
• Full course of treatment

40
Antibiotic Therapy

• Selection of antibiotic
• No Certainly Bacterium
• Community-acquired bacterial infection
• Nosocomial infection acquired in a hospital
• Broad-spectrum antibiotic coverage as noted below
• Children under age 3 months
• Cefotaxime and ampicillin
• Ceftriaxone and ampicillin (children over age
  1months)
• Children over 3 months
• Cefotaxime or Ceftriaxone or ampicillin and
  chloramphenicol

41
Antibiotic Therapy

• Certainly Bacterium
• Once the pathogen has been identified and the
  antibiotic sensitivities determined, the most
  appropriate drugs should selected.
• N meningitidis penicillin, tert- cephalosporin
  
• S pneumoniae penicillin, tert- cephalosporin,
  vancomycin
• H influenzae ampicillin, tert- cephalosporin
• S aureus penicillin, nefcillin, vancomycin
• E coli ampicillin, chloramphenicol, tert-
  cephalosporin

42
Antibiotic Therapy

• Course of treatment
• 7 days for meningococcal infection
• 1014 days for H influenzae or S pneumoniae
  infection
• More than 21 days for S aureus or E coli
  infection
• 1421 days for other organisms

43
Treatment General and Supportive Measures

• Monitor of vital sign
• Correcting metabolic imbalances
• Supplying sufficient heat quantity
• Correcting hypoglycemia
• Correcting metabolic acidemia
• Correcting fluids and electrolytes disorder
• Application of cortical hormone
• Lessening inflammatory reaction
• Lessening toxic symptom
• lessening cerebral edema

44
General and Supportive Measures

• Treatment of hyperpyrexia and seizures
• Pyretolysis by physiotherapy and/or drug
• Convulsive management
• Diazepam
• Phenobarbital
• Subhibernation therapy
• Treatment of increased intracranial pressure
• Dehydration therapy
• 20Mannitol 5ml/kg vi q6h
• Lasix 1-2mg/kg vi

45
General and Supportive Measures

• Treatment of septic shock and DIC
• Volume expansion
• Dopamine
• Corticosteroids
• Heparin
• Fresh frozen plasma
• Platelet transfusions

46
Treatment Complication Measures

• Subdural effusions
• Subduaral pricking
• Draw-off effusions on one side is 20-30ml/time.
• Once daily or every other day is requested.
• Time cell of pricking may be prolonged after 2
  weeks.
• Ependymitis
• Ventricular puncture drainage
• Pressure in ventricle be depressed.
• Ventricular puncture may give ventricle an
  injection of antibiotic.

47
Complication Measures

• Hydrocephalus
• Operative treatment
• Adhesiolysis
• By-pass operation of cerebrospinal fluid
• Dilatation of aqueduct
• SIADH (Cerebral hyponatremia)
• Restriction of fluid
• supplement of serum sodium
• diuretic

48
Prognosis

• Appropriate antibiotic therapy reduces the
  mortality rate for bacterial meningitis in
  children, but mortality remain high.
• Overall mortality in the developed countries
  ranges between 5 and 30.
• 50 percent of the survivors have some sequelae of
  the disease.

49
Prognosis

• Prognosis depends upon many factors
• Age
• Causative organism
• Number of organisms and bacterial virulence
• Duration of illness prior to effective antibiotic
  therapy
• Presence of disorders that may compromise host
  response to infection